function init() {

    //新建点矢量图层
    pointLayer = new SuperMap.Layer.Vector("pointLayer");

    //新建线矢量图层
    lineLayer = new SuperMap.Layer.Vector("lineLayer");

    //新建线矢量图层
    polygonLayer = new SuperMap.Layer.Vector("polygonLayer");

    //对线图层应用样式style（前面有定义）
    lineLayer.style = style;

    drawPoint = new SuperMap.Control.DrawFeature(pointLayer, SuperMap.Handler.Point, {
        multi: true
    });

    //创建画线控制，图层是lineLayer;这里DrawFeature(图层,类型,属性)；multi:true在将要素放入图层之前是否现将其放入几何图层中
    drawLine = new SuperMap.Control.DrawFeature(lineLayer, SuperMap.Handler.Path, {
        multi: true
    });

    drawPolygon = new SuperMap.Control.DrawFeature(polygonLayer, SuperMap.Handler.Polygon);

    /*
    注册featureadded事件,触发drawCompleted()方法
    例如注册"loadstart"事件的单独监听
    events.on({ "loadstart": loadStartListener });
    */
    drawLine.events.on({
        "featureadded": drawCompleted1
    });
    //*定义layer图层，TiledDynamicRESTLayer：分块动态 REST 图层
    layer = new SuperMap.Layer.TiledDynamicRESTLayer("China", url, {
        transparent: true,
        cacheEnabled: true
    }, {
        maxResolution: "auto"
    });
    //为图层初始化完毕添加addLayer()事件
    layer.events.on({
        "layerInitialized": addLayer
    });
    map = new SuperMap.Map("map", {
        controls: [
            // new SuperMap.Control.LayerSwitcher(),
            new SuperMap.Control.Navigation({
                dragPanOptions: {
                    enableKinetic: true
                }
            }),
            drawPoint, drawLine, drawPolygon
        ]
    });
    //初始化简易缩放控件类
    zoom = new SuperMap.Control.Zoom();
    //加载平移缩放控件
    map.addControl(new SuperMap.Control.PanZoomBar(), new SuperMap.Pixel(0, 400));
    //加载比例尺控件
    map.addControl(new SuperMap.Control.ScaleLine(), new SuperMap.Pixel(25, 550));
    //加载地图鹰眼控件
    map.addControl(new SuperMap.Control.OverviewMap(), new SuperMap.Pixel(300, 300));
    //加载地图图层切换控件
    map.addControl(new SuperMap.Control.LayerSwitcher(), new SuperMap.Pixel(60, 370));
}

function addLayer() {
    map.addLayers([layer, pointLayer, lineLayer, polygonLayer]);
    map.setCenter(new SuperMap.LonLat(5105, -3375), 2);
}

function draw_point() {
    pointLayer.removeAllFeatures();
    drawPoint.activate();
}

function distanceMeasure() {
    lineLayer.removeAllFeatures();
    drawLine.activate();
}

function draw_polygon() {
    polygonLayer.removeAllFeatures();
    drawPolygon.activate();
}

//绘完触发事件
function drawCompleted1(drawGeometryArgs) {
    //停止画面控制
    drawLine.deactivate();
    //获得图层几何对象
    var geometry = drawGeometryArgs.feature.geometry,
        measureParam = new SuperMap.REST.MeasureParameters(geometry),
        /* MeasureParameters：量算参数类。 客户端要量算的地物间的距离或某个区域的面积*/
        myMeasuerService = new SuperMap.REST.MeasureService(url); //量算服务类，该类负责将量算参数传递到服务端，并获取服务端返回的量算结果
    myMeasuerService.events.on({
        "processCompleted": measureCompleted1
    });

    //对MeasureService类型进行判断和赋值，当判断出是LineString时设置MeasureMode.DISTANCE，否则是MeasureMode.AREA

    myMeasuerService.measureMode = SuperMap.REST.MeasureMode.DISTANCE;

    myMeasuerService.processAsync(measureParam); //processAsync负责将客户端的量算参数传递到服务端。
}

//测量结束调用事件
function measureCompleted1(measureEventArgs) {
    var distance = measureEventArgs.result.distance;
    var unit = measureEventArgs.result.unit;
    alert("量算结果:" + distance + "米");
}

//移除图层要素
// function clearFeatures() {
//     lineLayer.removeAllFeatures();
// }